- Orientation of fluorinated cholesterol in lipid bilayers analyzed by 19F tensor calculation and solid-state NMR
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6-F-cholesterol was reported to exhibit biological and interfacial properties similar to unmodified cholesterol. We have also found that 6-F-cholesterol mimicked the cholesterol activity observed in the systems of amphotericin B and lipid rafts. However, to use 6-F-cholesterol as a molecular probe to explore molecular recognition in membranes, it is indispensable to have detailed knowledge of the dynamic and orientation properties of the molecule in membrane environments. In this paper, we present the molecular orientation of 6-F-cholesterol (30 mol %) in dimyristoylphosphatidylcholine (DMPC) bilayers revealed by combined use of 19F chemical shift anisotropy (CSA), 2H NMR, and C-F rotational echo double resonance (REDOR) experiments. The axis of rotation of 6-F-cholesterol was shown to be in a similar direction to that of cholesterol in DMPC bilayers, which is almost parallel to the long axis of the molecular frame. The molecular order parameter of 6-F-cholesterol was determined to be ca. 0.85, which is within the range of reported values of cholesterol. These findings suggest that the dynamic properties of 6-F-cholesterol in DMPC are quite similar to those of unmodified cholesterol; therefore, the introduction of a fluorine atom at C6 has virtually no effect on cholesterol dynamics in membranes. In addition, this study demonstrates the practical utility of theoretical calculations for determining the 19F CSA principal axes, which would be extremely difficult to obtain experimentally. The combined use of quantum calculations and solid-state 19F NMR will make it possible to apply the orientation information of 19F CSA tensors to membrane systems.
- Matsumori, Nobuaki,Kasai, Yusuke,Oishi, Tohru,Murata, Michio,Nomura, Kaoru
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- Self-assembly of novel cholesterol derivative based on hydrogen bond
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In this paper, a novel cholesterol derivative was found that it can form regular arrangement with millimeter size when we investigated the synthesis of new cholesterol monomer. The quite interesting thing is that the arrangement can form on common glass sheet after the sample is heating above its melting point and then cooling to room temperature. This is different from most reported regular arrangements formed in solutions. According to the single crystal results of the sample, we believe that the arrangement formed in solid state can be attributed to hydrogen bonding formed between molecular and Van der Waals force among molecular.
- Yu, Yun-Long,Du, Hai-Yan,Zhang, Jun-Hua
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- Characterization of heparin and severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) spike glycoprotein binding interactions
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Severe acute respiratory syndrome-related coronavirus 2 (SARS-CoV-2) has resulted in a pandemic and continues to spread around the globe at an unprecedented rate. To date, no effective therapeutic is available to fight its associated disease, COVID-19. Our discovery of a novel insertion of glycosaminoglycan (GAG)-binding motif at S1/S2 proteolytic cleavage site (681–686 (PRRARS)) and two other GAG-binding-like motifs within SARS-CoV-2 spike glycoprotein (SGP) led us to hypothesize that host cell surface GAGs may interact SARS-CoV-2 SGPs to facilitate host cell entry. Using a surface plasmon resonance direct binding assay, we found that both monomeric and trimeric SARS-CoV-2 SGP bind more tightly to immobilized heparin (KD = 40 pM and 73 pM, respectively) than the SARS-CoV and MERS-CoV SGPs (500 nM and 1 nM, respectively). In competitive binding studies, the IC50 of heparin, tri-sulfated non-anticoagulant heparan sulfate, and non-anticoagulant low molecular weight heparin against SARS-CoV-2 SGP binding to immobilized heparin were 0.056 μM, 0.12 μM, and 26.4 μM, respectively. Finally, unbiased computational ligand docking indicates that heparan sulfate interacts with the GAG-binding motif at the S1/S2 site on each monomer interface in the trimeric SARS-CoV-2 SGP, and at another site (453–459 (YRLFRKS)) when the receptor-binding domain is in an open conformation. The current study serves a foundation to further investigate biological roles of GAGs in SARS-CoV-2 pathogenesis. Furthermore, our findings may provide additional basis for further heparin-based interventions for COVID-19 patients exhibiting thrombotic complications.
- Dordick, Jonathan S.,Fu, Li,Fuster, Mark M.,Grant, Oliver C.,Jin, Weihua,Kim, So Young,Linhardt, Robert J.,Montgomery, David W.,Sood, Amika,Woods, Robert J.,Zhang, Fuming
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- 3β-Acetoxy cholest-5-ene crystals: Catalytic synthesis, structural elucidation, contribution of intermolecular interactions and density functional theory calculations
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In this work, we present the synthesis of 3β-acetoxy cholest-5-ene using zinc triflate Zn(OTf)2 as a catalyst. The synthesized molecule has been characterized by single crystal XRD, spectroscopic techniques and density functional theory (DFT) calculations. The compound crystallizes in the monoclinic space group P21 with cell dimensions, a = 16.585(2) ?, b = 9.5175(12) ?, c = 17.656(2) ?, α = 90.00, β = 106.369(4), γ = 90.00. The systematic analysis of intermolecular interactions in crystal structure was accomplished by Hirshfeld surface analysis and fingerprint plot. Molecules are linked by a combination of C?H, C?C, H?H and O?H contacts, which have clear signatures in the fingerprint plots. The theoretical DFT/B3LYP calculations have been attempted to obtain the optimized geometry, IR/NMR spectra, natural bond orbitals, frontier molecular orbitals and various structure based molecular properties. We compared the conformations of the compound in solid state and in solution by calculation of dihedral angles and coupling constant values.
- Ahmad, Shabbir,Ahmed, Musheer,Alam, Mohammad Jane,Amer, Bushra,Mashrai, Ashraf
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- Site-selective and metal-free aliphatic C-H oxidation enabled synthesis of [5,24,25-d3]-(25s)-δ7-dafachronic acid
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Steroid hormones play significant roles in both worms and mammalians. (25S)-Δ7-Dafachronic acid (Δ7-DA, 1) is a member of the dafachronic acid hormonal series that regulates both development and lifespan of C. elegans. Despite its importance, effective tools for the illumination of its mode of action are lacking. Herein, we report an efficient synthesis of trideuterated Δ7-DA, [5,24,25-D3]-(25S)-Δ7-dafachronic acid ([D3]-Δ7-DA, 2), as a useful chemical tool for subsequent biological studies. Key steps for this bioinspired synthesis approach include site-selective aliphatic C-H oxidation mediated by methyl(trifluoromethyl)dioxirane (TFDO), and the iridium/phosphine-oxazoline-catalyzed late-stage asymmetric deuterium reduction. Bio is best! [5,24,25-D3]-(25S)-Δ7-Dafachronic acid, an isotope-labeled steroid hormone has been synthesized in 14 steps from cholesterol inspired by biosynthesis. Key steps include a site-selective and metal-free aliphatic C-H oxidation and a late-stage catalytic asymmetric deuteration (see scheme). [5,24,25-D3]-(25S)-Δ7-Dafachronic acid will be severed as an effective chemical tool for the illumination of novel molecular mechanisms of longevity.
- Liu, Weilong,Li, Xiangke,Chen, Jie,Li, Tiemei,Dong, Mengqiu,Lei, Xiaoguang
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- IMIDAZOLE MEDIATED ACYLATION OF CHOLESTEROL IN FUNCTIONAL VESICLES: A SIMPLE ANALOGUE OF LECITHIN:CHOLESTEROL ACYLTRANSFERASE
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Imidazole-functionalized surfactants transfer acetyl groups from p-nitrophenyl acetate to cholesterol in vesicular coaggregates.
- Moss, Robert A.,Bhattacharya, Santanu,Okumura, Yukihisa
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- Method for synthesizing cholesterol by taking BA as raw material
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The invention discloses a method for synthesizing cholesterol by taking BA as a raw material. A plant source raw material 21-hydroxy-20-methylpregna-4-en-3-one, also known as Shuangjiangchun or BA is taken as a raw material, and the cholesterol is synthesized by the steps of oxidation, Wittig reaction, acetylation, reduction, selective hydrogenation reduction and the like. The raw materials for synthesizing cholesterol are plant sources, the price is low, the safety is high, the risk of pathogenic bacteria and virus infection is avoided, and the synthesis method is easy to operate, high in yield, few in side reaction, environmentally friendly, good in economical efficiency and convenient for industrial production; and the invention solves the safety problem of the existing cholesterol product and the problems of high cost, environmental unfriendliness and unsuitability for large-scale industrial production in the synthesis technology.
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Paragraph 0147-0149
(2021/08/14)
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- Novel industrial method for preparing vitamin D3 by taking stigmasterol as raw material
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The invention provides a novel industrial method for preparing vitamin D3 by taking stigmasterol as a raw material. The method comprises the following steps: sequentially carrying out hydroxyl acetylation, side chain oxidation, side chain isopentane reduction and hydrogenation on stigmasterol to obtain cholesterol acetate, and then sequentially carrying out oxidation, hydrazone formation, hydrazone removal, hydrolysis, illumination and the like to obtain the vitamin D3. The invention provides a novel method for preparing vitamin D3 from stigmasterol, and the method has the advantages of mild reaction conditions and high yield, and is suitable for industrial production.
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- KMnO4-catalyzed chemoselective deprotection of acetate and controllable deacetylation-oxidation in one pot
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A novel and efficient protocol for chemoselective deacetylation under ambient conditions was developed using catalytic KMnO4. The stoichiometric use of KMnO4 highlighted the dual role of a heterogeneous oxidant enabling direct access to aromatic aldehydes in one-pot sequential deacetylation-oxidation. The reaction employed an alternative solvent system and allowed the clean transformation of benzyl acetate to sensitive aldehyde in a single step while preventing over-oxidation to acids. Use of inexpensive and readily accessible KMnO4 as an environmentally benign reagent and the ease of the reaction operation were particularly attractive, and enabled the controlled oxidation and facile cleavage of acetate in a preceding step. This journal is
- Gurawa, Aakanksha,Kumar, Manoj,Rao, Dodla S.,Kashyap, Sudhir
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supporting information
p. 16702 - 16707
(2020/10/27)
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- HALOGENATED CHOLESTEROL ANALOGUES AND METHODS OF MAKING AND USING SAME
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Provided herein are halogenated cholesterol analogues, including methods of making and using the same. Also provided are methods of making radiolabeled cholesterol analogues including admixing an epoxide with a fluorine-18 source under conditions to form a radiofluorinated cholesterol analogue.
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Paragraph 0088-0091
(2020/05/12)
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- Synthesis and search for 3β,3′β-disteryl ethers after high-temperature treatment of sterol-rich samples
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It has been proven that at increased temperature, sterols can undergo various chemical reactions e.g., oxidation, dehydrogenation, dehydration and polymerisation. The objectives of this study are to prove the existence of dimers and to quantitatively analyse the dimers (3β,3′β-disteryl ethers). Sterol-rich samples were heated at 180 °C, 200 °C and 220 °C for 1 to 5 h. Quantitative analyses of the 3β,3′β-disteryl ethers were conducted using liquid extraction, solid-phase extraction and gas chromatography coupled with mass spectrometry. Additionally, for the analyses, suitable standards were synthetized from native sterols. To identify the mechanism of 3β,3′β-disteryl ether formation at high temperatures, an attempt was made to use the proposed synthesis method. Additionally, due to the association of sterols and sterol derivatives with atherosclerosis, preliminary studies with synthetized 3β,3′β-disteryl ethers on endothelial cells were conducted.
- Bus, Katarzyna,Ofiara, Karol,Sitkowski, Jerzy,Szterk, Arkadiusz,Zmys?owski, Adam
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- New industrial method for producing vitamin D3 by taking wool fat as raw material
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The invention provides a new industrial method for producing vitamin D3 by taking wool fat as a raw material. The new industrial method comprises the following steps: carrying out saponification and primary purification on the wool fat in a low alcohol solution, thus obtaining a cholesterol crude product; directly carrying out acetylation on the cholesterol crude product, thus obtaining high-purity cholesterol acetate; then sequentially carrying out oxidizing, hydrazone forming, hydrazone removing, hydrolyzing, illuminating and the like, thus obtaining the vitamin D3. A production technology disclosed by the invention is efficient, green and environment-friendly, is high in product yield and is suitable for industrial production, and the manufacturing cost of the vitamin D3 is greatly reduced; a saponification technology is ingenious in filtrate treatment, has no generation of waste liquid and waste and is more beneficial for environment protection.
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Paragraph 0036; 0037
(2019/06/13)
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- Novel Method for O-Acetylation of Cholesterol, Allobetulin, and Betulin
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Primary and secondary triterpene alcohols were acetylated for the first time using tetraacetylglycoluril (TAGU). Cholesterol, allobetulin, and betulin acetates were obtained in high yields. The acetylation used p-TsOH or TFA in refluxing CHCl3. TFA was found to be an effective acetylation catalyst.
- Arrous, Salah,Boudebouz, Imene,Bakibaev, Abdigali,Hoang, Phuoc,Parunov
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p. 482 - 484
(2019/07/02)
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- B-cholesterol-reducingoxidation derivativeand synthesis method and application thereof
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The invention provides a B-cholesterol-reducingoxidation derivative. The structural formula of the compound is as shown in the description, wherein, R is CH3 or CH3CH2CH2 or CH3CH2CH2CH2. The B-cholesterol-reducingoxidation derivativecompound can significantly inhibit growth and proliferation of tumor cellsof human breast cancer cells, human ductalbreast cancer cells and human ovarian cancer cells,and can be used as drug intermediates or drugs and applied to manufacturing and use of different drugs.
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Paragraph 0024-0025; 0029
(2019/06/30)
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- 3-acetyl-5-hydroxy-B-norcholesterol-6-(N-methyl)thiosemicarbazone, and preparation method and use thereof
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The invention discloses a 3-acetyl-5-hydroxy-B-norcholesterol-6-(N-methyl)thiosemicarbazone, and a preparation method and a use thereof. The structural formula of the 3-acetyl-5-hydroxy-B-norcholesterol-6-(N-methyl)thiosemicarbazone is shown in the description. The prepared 3-acetyl-5-hydroxy-B-norcholesterol-6-(N-methyl)thiosemicarbazone has obvious inhibitory effects on various tumor cell linessuch as liver cancer, lung cancer, gastric cancer, cervical cancer, prostate cancer and colon cancer, has a low toxicity, and is not prone to produce drug resistance. The present invention also provides the preparation method and the use of the compound. The preparation method is simple, is easy to implement, and facilitates market promotion and application.
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Paragraph 0035-0037
(2019/10/23)
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- Diazepinium perchlorate: a neutral catalyst for mild, solvent-free acetylation of carbohydrates and other substances
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Diazepinium perchlorate, an essentially neutral organic salt possessing excellent stability, has been found to be well suited for the acetylation of free as well as partially protected sugars, phenols, thiophenols, thiols and other alcohols as well as amines. The diazepinium perchlorate-catalyzed acetylation is mild, organic and solvent-free and leaves acid sensitive protecting groups such as TBDMS/TBDPS/Tr ethers and isopropylidene/benzylidene acetals present on a substrate unaffected. Regioselective hydroxyl protection in partially protected carbohydrate derivatives/polyhydroxylic compounds was possible and was proved to be a convenient time-saving alternative to the conventional synthesis of such compounds. Easy preparation of the catalyst, mild reaction conditions and an environmentally benign protocol are some of the notable features of this reaction. The results obtained on the acetylation of phenols and thiophenols could be rationalized through their local nucleophilicity index obtained from DFT calculations.
- Giri, Santosh Kumar,Gour, Rajesh,Kartha, K. P. Ravindranathan
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p. 13653 - 13667
(2017/03/11)
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- Synthesis and biological activity evaluation of novel peroxo-bridged derivatives as potential anti-hepatitis B virus agents
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Previous studies have demonstrated that natural steroid compounds containing a peroxide bridge exhibited potential anti-hepatitis B virus activity. To continue our research, a simple and regioselective methodology, using Eosin Y as a clean photosensitized oxidation catalyst, was developed for the synthesis of a peroxide bridge in steroids. The method that using Eosin Y as the catalyst was exposed to visible light and furbished in high yields, did not involve tedious work-up or purification, and avoided using environmentally hazardous solvents. It can be regarded as a green protocol. Moreover, a series of cholesterol and β-sitosterol derivatives containing a peroxide bridge were synthesized using this method and screened for their anti-HBV activity. Among the compounds synthesized in this research, 5α,8α-cyclicobioxygen-6-vinyl-3-oxo-cholesterone (1f, 3.13 μg ml?1) had the most potent activity with inhibition rates of 77.45% ± 6.01% and 58.73% ± 8.64% on the secretion of HBsAg and HBeAg antigens, respectively, after 8 days. Further acute toxicity test showed that the LD50 value of compound 1f was 362.46 mg kg?1 after an intraperitoneal injection in mice. Moreover, structure-activity relationships of cholesterol and β-sitosterol derivatives were briefly discussed.
- Jia, Menglu,Zhao, Rui,Xu, Bing,Yan, Wenqiang,Chu, Fuhao,Gu, Hongshun,Xie, Tianxin,Xiang, Hongjun,Ren, Jian,Chen, Dagang,Wang, Penglong,Lei, Haimin
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supporting information
p. 148 - 151
(2017/02/05)
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- NANOEMULSIONS AND METHODS FOR CANCER THERAPY
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An oxysterol or oxysterol-like compound is provided, which finds use in treating and/or targeting cancer.
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Page/Page column 22
(2017/12/15)
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- Ethyl acetate as an acetyl surrogate for the iodine catalyzed acetylation of alcohols
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The use of readily available ethyl acetate in the presence of iodine as an alternative acetylating agent is reported. Amines and phenols were unreactive under the examined reaction conditions, indicating that the method is highly chemoselective.
- Basumatary, Grace,Bez, Ghanashyam
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supporting information
p. 4312 - 4315
(2017/10/13)
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- Steroid zinc metal complex and method of preparing the same and in the preparation of anti-stomach cancer application of the medicament (by machine translation)
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A steroid zinc metal complex and method of preparing the same and in the preparation of anti-stomach cancer application of the medicament. Complex is the chemical name: dichloroborane · [3 β-acetoxy, cholest-5-ene-7- shrinks the ammonia thiourea-N, S] zinc (II) are, the structural formula is as follows: The preparation method comprises the following steps: 1) 3 β-acetoxy, cholest-5-ene preparation; 2) 3 β-acetoxy, cholest-5-ene-7-one preparation; 3) 3 β-acetoxy, cholest-5-ene-7- shrinks the ammonia thiourea preparation; 4) dichloroborane · [3 β-acetoxy, cholest-5-ene-7- shrinks the ammonia thiourea-N, S] preparation of a zinc (II). The in vitro anti-tumor experiments show that, · dichloroborane of the present invention [3 β-acetoxy, cholest-5-ene-7- shrinks the ammonia thiourea-N, S] zinc (II) are compounds with strong anti-gastric cancer activity. (by machine translation)
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Paragraph 0033-0034
(2017/02/09)
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- Synthetic study of strongylophorines: stereoselective construction of the characteristic lactone bridge
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Herein, we report an efficient construction of the lactone bridge of strongylophorine-2, which is a meroditerpenoid isolated from Strongylophora durissima and an inhibitor for HIF-1 transcriptional pathway. Starting from dehydroepiandrosterone acetate, the characteristic lactone has been constructed in 5.4% over 18 steps by employing, (1) modified oxy radical-mediated C–H functionalization at the C24 methyl group, and (2) four-step manipulation of C4 quaternary carbon stereogenic center. The lactone synthesized here is expected as a precursor for (8-desmethyl)strongylophorine-2 which is of particular interest in terms of structure–activity relationships in the inhibition of HIF-1 transcriptional pathway.
- Oikawa, Yuya,Uchiyama, Daiki,Shirasawa, Takuya,Oikawa, Masato,Ishikawa, Yuichi
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supporting information
p. 3949 - 3951
(2016/08/09)
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- TiCl4/Et3N-Mediated Condensation of Acetate and Formate Esters: Direct Access to β-Alkoxy- and β-Aryloxyacrylates
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A methodology to build (E)-β-alkoxy- and (E)-β-aryloxyacrylate moieties from acetate and formate esters promoted by the TiCl4/Et3N system is presented. The reaction is compatible with a broad range of structural skeletons and elapses through an unusual condensation pathway. Taking into account the obtained results, we propose a plausible mechanism involving a bimetallic titanium intermediate for this type of transformation.
- álvarez-Calero, José María,Jorge, Zacarías D.,Massanet, Guillermo M.
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supporting information
p. 6344 - 6347
(2016/12/23)
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- Tunable microwave-assisted method for the solvent-free and catalyst-free peracetylation of natural products
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Background: The peracetylation is a simple chemical modification that can be used to enhance the bioavailability of hydrophilic products and to obtain safe and stable pro-drugs. Results: A totally green, solvent-free and catalyst-free microwave (MW)-assisted method for peracetylation of natural products such as oleuropein, alpha-hederin, quercetin and rutin is presented. By simply tuning the MW heating program, polyols with chemical diverse -OH groups or thermolabile functionalities can be peracetylated to improve the biological activity without degradation of the natural starting molecules. An evaluation of the process greenness was performed. Conclusion: The method is potentially universally applicable for green acetylation of hydrophilic biological molecules, potentially easily scalable for industrial applications, including pharmaceutical, cosmetic and food industry.
- Oliverio, Manuela,Costanzo, Paola,Nardi, Monica,Calandruccio, Carla,Salerno, Raffaele,Procopio, Antonio
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supporting information
p. 2222 - 2233
(2016/11/17)
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- Oxysterols: Synthesis and anti-leishmanial activities
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Oxygenated sterols (2-16) were synthesized by skeletal rearrangement of steroidal allylic alcohols. All the derivatives were screened for their anti-leishmanial activities. Compounds 3, 11 and 12 showed potent activities. Compound 12 was found least toxic and induced highest nitric oxide (NO) at 48 h. Least toxicity of compound 12 on splenocytes validated its best anti-amastigote effect and induction of NO.
- Ghosh, Pranab,Ghosh, Ashim,Mandal, Amitava,Sultana, Sirin Salma,Dey, Somaditya,Pal, Chiranjib
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- 7-keto cholesteryl-9-carboxyl nonane and synthesis method of fluorescent marker thereof
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The invention relates to 7-keto cholesteryl-9-carboxyl nonane and a synthesis method of a fluorescent marker thereof. Cholesterol and azelaic acid are used as raw materials, 1,3-dicyclohexyl carbodiimide and 4-dimethylamino pyridine are used as a catalyst for synthesis reaction, and dichloromethane is used as a solvent to establish an oxidation system, and finally the 7-keto cholesteryl-9-carboxyl nonane is obtained through fat reduction reaction. The synthesis method of the 7-keto cholesteryl-9-carboxyl nonane is simple and convenient to operate, the raw materials are easy to obtain, the impurity content is low, and the production cost is low. The invention further provides a synthesis method of NBD-fluorescent group introduced 7-keto cholesteryl-9-carboxyl nonane. NBD-fluorescent groups are introduced on the basis that a basic framework structure is ensured, and finally NBD-oxLig-1 is synthesized so that the 7-keto cholesteryl-9-carboxyl nonane (oxLig-1) can produce spontaneous fluorescence and is used for tracer application in cell biology.
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Paragraph 0047; 0048; 0049; 0050; 0051
(2016/10/17)
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- Method for synthesizing cholesterol by using stigmasterol degradation products as raw materials
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The invention provides a method for synthesizing cholesterol by using stigmasterol degradation products as raw materials. The method comprises the following steps: 1) performing an etherification reaction on 3-carbonyl-4-pregnene-22-aldehyde and triethyl orthoformate to obtain 3-ethyoxyl-3,5-pregnadiene-22-aldehyde; 2) preparing a 3-methylbutyltriphenyl phosphonium chloride solution; 3) adding potassium tert-butoxide into the 3-methylbutyltriphenyl phosphonium chloride solution, performing a wittig reaction on the 3-methylbutyltriphenyl phosphonium chloride solution and the 3-ethyoxyl-3,5-pregnadiene-22-aldehyde to obtain 3-ethyoxyl-3,5,22-triene cholestane; 4) catalyzing the 3-ethyoxyl-3,5,22-triene cholestane to perform a selective hydrogenation reaction to obtain 3-ethyoxyl-5-ene cholestane; 5) performing a reaction on the 3-ethyoxyl-5-ene cholestane and acetic anhydride to obtain 3-acetyl-5-ene cholestane; 6) performing a hydrolysis reaction on the 3-acetyl-5-ene cholestane to obtain the cholesterol. The synthesizing method is simple in process, and the mole yield of the cholesterol exceeds 85 percent by using the stigmasterol degradation products which are cheap and easily obtained as the raw materials; the production cost is low, the process is environmentally friendly, and the method is economical and environmentally friendly, and facilitates industrial implementation.
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- Site-Selective Acylations with Tailor-Made Catalysts
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The acylation of alcohols catalyzed by N,N-dimethylamino pyridine (DMAP) is, despite its widespread use, sometimes confronted with substrate-specific problems: For example, target compounds with multiple hydroxy groups may show insufficient selectivity for one hydroxyl, and the resulting product mixtures are hardly separable. Here we describe a concept that aims at tailor-made catalysts for the site-specific acylation. To this end, we introduce a catalyst library where each entry is constructed by connecting a variable and readily tuned peptide scaffold with a catalytically active unit based on DMAP. For selected examples, we demonstrate how library screening leads to the identification of optimized catalysts, and the substrates of interest can be converted with a markedly enhanced site-selectivity compared with only DMAP. Furthermore, substrate-optimized catalysts of this type can be used to selectively convert "their" substrate in the presence of structurally similar compounds, an important requisite for reactions with mixtures of substances. Substrate-optimized catalysts: Site- selective acylations were achieved using substrate-optimized catalysts (see scheme) as identified from a library screening. The catalysts are composed of low-molecular-weight peptides that are readily tuned through variation of the amino acid sequence, and one amino acid was connected to DMAP to ensure catalytic activity. These substrate-optimized catalysts were also applied to selectively convert one substrate in the presence of a structurally similar compound.
- Huber, Florian,Kirsch, Stefan F.
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supporting information
p. 5914 - 5918
(2016/04/26)
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- Synthesis and characterization of ionic liquid immobilized on magnetic nanoparticles: A recyclable heterogeneous organocatalyst for the acetylation of alcohols
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Herein, we describe a simple and efficient procedure for the preparation of 3-((3-(trisilyloxy)propyl)propionamide)-1-methylimidazolium chloride ionic liquid supported on magnetic nanoparticle (TPPA-IL-Fe3O4). The structure of this magnetic ionic liquid is fully characterized by FT-IR, TGA, XRD, VSM, SEM, EDX and DLS techniques. TPPA-IL-Fe3O4 is employed as a catalyst for the acetylation of alcohols with acetic anhydride under mild and heterogeneous conditions at room temperature with good to excellent yields. The magnetic catalyst could be readily separate from the reaction media by simple magnetic decantation, and reused several times without significant loss of its catalytic activity.
- Ghorbani-Choghamarani, Arash,Norouzi, Masoomeh
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p. 832 - 840
(2015/11/16)
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- Transesterification Reactions Catalyzed by a Recyclable Heterogeneous Zinc/Imidazole Catalyst
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We report the development of a universal and recyclable heterogeneous zinc/imidazole catalyst. The catalyst is recoverable through simple filtration and can be reused at least five times, retaining its catalytic activity. Leached zinc species were not responsible for the observed catalysis based on the hot filtration test and ICP-MS analysis. The heterogeneous zinc catalyst also promotes chemoselective transesterification over amidation. (Figure presented.).
- Nakatake, Daiki,Yazaki, Ryo,Matsushima, Yoshimasa,Ohshima, Takashi
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supporting information
p. 2569 - 2574
(2016/08/16)
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- Synthesis and characterization of steroidal heterocyclic compounds, DNA condensation and molecular docking studies and their in vitro anticancer and acetylcholinesterase inhibition activities
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A facile, convenient and efficient approach for the synthesis of a new series of steroidal heterocyclic compounds (4-12) by reacting a mixture of compounds (1e-3e) with o-aminothiophenol/o-aminophenol/o-phenylenediamine is reported. The structural assignment of products is confirmed on the basis of IR, 1H NMR, 13C NMR, MS and analytical data. The compounds obey the Lipinski's 'Rule of Five' analysis based on computational prediction and pharmacokinetic properties. The anticancer activity has been tested in vitro against three cancer cell lines Hep3B (human hepatocellular carcinoma), MCF7 (human breast adenocarcinoma), HeLa (human cervical carcinoma) and one non-cancer normal cell i.e. PBMCs (peripheral blood mononuclear cell) by MTT assay. In addition, the synthesized compounds are also tested for their in vitro antioxidant activity by various reported methods in which compounds 10-12 exhibited good antioxidant activity. Nonenzymatic degradation of DNA has been investigated. The acetylcholinesterase (AChE) inhibitor activities of the steroidal derivatives are also evaluated using Ellman's method. Moreover, the application of compound 6 as a DNA gene transporter is evaluated by DNA condensation and ascertained by employing TEM and AFM, which illustrate that the compound 6 induces the condensation of CT-DNA. Molecular docking studies further characterize the interaction of the synthesized compounds with DNA. 2015
- Ali, Abad,Asif, Mohd,Khanam, Hena,Mashrai, Ashraf,Sherwani, Mohd Asif,Owais, Mohammad,Shamsuzzaman
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p. 75964 - 75984
(2015/09/28)
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- Allylic oxidation of steroidal olefins by vanadyl acetylacetonate and tert-butyl hydroperoxide
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Abstract Readily available vanadyl acetylacetonate was found to oxidize the allylic sites of Δ5 steroidal alcohols without protection of hydroxyl groups. Cholesterol, dehydroepiandrosterone, cholesterol benzoate, cholesterol acetate, pregnenolone, and 5-pregnen-3,20-diene were oxidized to 7-keto products using vanadyl acetylacetonate in one pot reactions at room temperature in the presence of oxygen and water.
- Grainger, Wendell S.,Parish, Edward J.
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p. 103 - 109
(2015/06/30)
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- MnO2/TBHP: A Versatile and User-Friendly Combination of Reagents for the Oxidation of Allylic and Benzylic Methylene Functional Groups
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In the presence of activated MnO2, tert-butyl hydroperoxide (TBHP) in CH2Cl2 is able to oxidize the allylic and benzylic methylene groups of different classes of compounds. I describe a one-pot oxidation protocol based on two sequential steps. In the first step, carried out at low temperature, MnO2 catalyses the oxidation of the methylene group. This is followed by a second step where reaction temperature is increased, allowing MnO2 both to catalyse the decomposition of unreacted TBHP and to oxidize allylic alcohols that could possibly be formed. The proposed oxidation procedure is generally applicable, although its efficiency, regioselectivity, and chemoselectivity are strongly dependent on the structure of the substrate. A simple and user-friendly synthetic procedure for the oxidation of allylic and benzylic methylene groups to the corresponding conjugated carbonyl derivatives is described. The proposed oxidation protocol is based on the combined use of MnO2 and tert-butyl hydroperoxide, and is generally applicable.
- Serra, Stefano
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p. 6472 - 6478
(2015/10/19)
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- PROCESS FOR PREPARATION OF 7-DEHYDROCHOLESTEROL
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The invention discloses an improved cost-effective process for preparation of 7-Dehydrocholesterol of formula I with good yield and purity, comprising:a) epimerizing 7(alpha+beta) bromo protected cholesterol in presence of tetrabutyl ammonium bromide in toluene or a ketonic solvent or combinations thereof to obtain predominantly 7.alpha-bromo 3-protected cholesterol; b) Reacting 7.apha-bromo 3- protected cholesterol with substituted or unsubstituted thiophenol or its salts in presence of a liquor ammonia to obtain predominantly 7β-thiophenyl)-3-protected cholesterol; c) Oxidizing 7. beta. - thiophenyl 3-protected cholesterol in presence of Cumene hydrogen peroxide and Titanium tetraisopropoxide to obtain 7. beta. -phenyl sulfoxide 3-protected cholesterol; d) Converting 7. beta. -phenyl sulfoxide 3-protected cholesterol into 7-Dehydro 3-protected cholesterol in presence of base; e) purifying 7-Dehydro 3-protected cholesterol by suspending in a suitable organic solvent; and f) Deprotecting the 7-Dehydro 3-protected cholesterol by treating with alkali in presence of methanol to obtain 7-Dehydrocholesterol followed by purification of 7-Dehydrocholesterol from an organic solvent.
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Page/Page column 8
(2015/11/27)
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- Selective reduction of α,β-unsaturated steroidal carbonyl compounds by NaBH4in presence of guanidine hydrochloride in dioxane
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A selective hydrogenation of α,β-unsaturated steroidal carbonyl compounds with NaBH4in the presence of guanidine hydrochloride in dioxane in good to excellent yields are described.
- Khan, Salman Ahmad,Asiri, Abdullah M.
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p. 6331 - 6334
(2015/02/19)
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- Chemoselective palladium-catalyzed oxidation of vinyl ether to acetate using hydrogen peroxide
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A practical and environmental-friendly method was developed to convert vinyl ether into acetate by using a palladium complex with phosphine ligand and hydrogen peroxide. The only by-product is water. Chemoselective oxidation of vinyl ether and tert-enamides to form acetate and N-acetyl amide with hydrogen peroxide in the presence of palladium complex having phosphine ligand was developed under mild reaction conditions. This process is environmentally friendly because it uses hydrogen peroxide as a clean oxidant, with water being the only byprocuct.
- Kon, Yoshihiro,Tanaka, Shinji,Nakashima, Takuya,Sato, Kazuhiko,Shimada, Hiromichi
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p. 749 - 756
(2014/07/22)
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- Synthesis and antimicrobial activity of novel oxysterols from lanosterol
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Chemically diverse oxysterols and their synthetic manipulations were carried out from variety of Δ8(9)-lanosterol derivatives and evaluated for their in vitro antimicrobial activities. Most of the synthesized oxysterols exhibited significant antifungal activity against the tested strains.
- Shingate, Bapurao B.,Hazra, Braja G.,Salunke, Deepak B.,Pore, Vandana S.,Shirazi, Fazal,Deshpande, Mukund V.
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p. 11155 - 11163
(2014/01/06)
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- Synthesis of steroidal thiazolidinones as antibacterial agents based on the in vitro and quantum chemistry calculation
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Steroidal thiazolidinone derivatives were prepared from the reaction of steroidal thiosemicarbazones with ethyl bromoacetate in dioxane. Steroidal thiosemicarbazones were prepared by reacting thiosemicarbazide with steroidal ketones. The structures of these compounds were elucidated by IR, 1HNMR, 13CNMR, and mass spectral study, and their purities were confirmed by elemental analyses. The antibacterial activities of these compounds were evaluated by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria, and then the minimum inhibitory concentration of compounds were determined. The results showed that steroidal thiazolidinone derivatives are better in inhibiting growth as compared with steroidal thiosemicarbazone derivatives of both types of the bacteria. Compounds 7 and 8 are better antibacterial agents as compared with standard drug, Amoxicillin. Based on the quantum chemistry calculation at the DFT/6-31G*level, the frontier molecular orbitals and electrostatic potential of compounds 7 and 8 were also discussed.
- Khan, Salman A.,Asiri, Abdullah M.,Sharma, Kamlesh
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p. 1998 - 2004
(2013/07/26)
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- Synthesis and biological studies of steroidal pyran based derivatives
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Steroid based cancer chemotherapeutic agents of the type 2′-amino-3′-cyanocholest-6-eno[5,7-de]4H-pyrans (1c-3c) have been synthesized and characterized by the various spectroscopic and analytical techniques. The DNA binding studies of compounds (1c-3c) with CT DNA were carried out by UV-vis and fluorescence spectroscopy and gel electrophoresis. The compounds (1c-3c) bind to DNA preferentially through electrostatic and hydrophobic interactions with Kb values found to be 5.4 × 103, 2.3 × 103 M-1 and 1.97 × 103 M-1, respectively indicating the higher binding affinity of compound (1c) towards DNA. The molecular docking study suggested that the electrostatic interaction of compounds (1c-3c) in between the nucleotide base pairs is due to the presence of pyran moiety in steroid molecule. All the compounds (1c-3c) cleave supercoiled pBR322 DNA via hydrolytic pathway, as validated by T4 DNA ligase assay. The compounds (1c-3c) were screened for in vitro cytotoxicity against the cancer and non-cancer cells SW480, A549, HepG2, HeLa, MCF-7, HL-60, DU-145, NL-20, HPC and HPLF by MTT assay. The compounds (1c-3c) were tested for genotoxicity (comet assay) involving apoptotic degradation of DNA and was analyzed by agarose gel electrophoresis and visualized by ethidium bromide staining. The results revealed that compound (1c) has better prospectus to act as cancer chemotherapeutic candidate which warrants further in vivo anticancer investigations.
- Shamsuzzaman,Dar, Ayaz Mahmood,Khan, Yusuf,Sohail, Aamir
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- Semisynthesis and quantitative structure-activity relationship (QSAR) study of some cholesterol-based hydrazone derivatives as insecticidal agents
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In continuation of our program aimed at the discovery and development of natural-product-based insecticidal agents, four series of novel cholesterol-based hydrazone derivatives were synthesized, and their insecticidal activity was tested against the pre-third-instar larvae of oriental armyworm, Mythimna separata (Walker) in vivo at 1 mg/mL. All the derivatives showed the better insecticidal activity than their precursor cholesterol. Quantitative structure-activity relationship (QSAR) model demonstrated that six descriptors such as RDF085v, Mor06u, Mor11u, Dv, HATS0v and H-046, are likely to influence the insecticidal activity of these compounds. Among them, two important ones are the Mor06u and RDF085v.
- Yang, Chun,Shao, Yonghua,Zhi, Xiaoyan,Huan, Qu,Yu, Xiang,Yao, Xiaojun,Xu, Hui
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supporting information
p. 4806 - 4812
(2013/09/02)
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- Novel synthesis strategy for the preparation of individual phytosterol oxides
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Sterols (cholesterol and phytosterols) are important structural components of cell membranes and major constituents of lipid metabolism. Research on their oxides, such as the factors affecting oxidation, oxides' structures, and qualitative and quantitative analysis, aroused more attention in this decade. However, the biological roles of individual phytosterol oxides are still unclear because no commercial individual phytosterol oxide standards are available. Different from the traditional chemical synthesis, in the present study, chemical synthesis from a starting phytosterol mixture followed with a semipreparative HPLC separation produced individual oxides. TLC and analytical HPLC were used here to not only monitor the reaction process but also specifically analyze the synthetic intermediates and oxides. The chromatographic results exhibited strict rules and similar characteristics. Finally, for the first time, four individual phytosterol oxides were successfully separated and collected by a semipreparative HPLC system, thus providing a novel strategy for the preparation of individual phytosterol oxides.
- Gao, Junlan,Yue, Qiulin,Ji, Yishun,Cheng, Beijiu,Zhang, Xin
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p. 982 - 988
(2013/08/24)
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- Sterol Derivatives and Their Synthesis and Use
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Sterol derivatives with structural formula I or II are disclosed, wherein R is defined as the description of the invention. Their synthesizing methods and anti-tumor use are also disclosed. Especially, the compound of formula I, in which R is O (i.e. the compound CL 168-6), has the anti-tumor therapeutic index of 49.3. The compound can be used to prepare a medicine for prevention or treatment of immunological diseases and cancers such as liver cancer and lung cancer.
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Page/Page column 5
(2012/06/01)
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- Synthesis and characterization of side-chain cholesterol derivatives based on double bond
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After steps of esterification, epoxidation and ring-opening, a series of novel monomers of 5-hydroxyl-6-methacryloyloxy-3-alkylate, CnCOOCh (n = 1, 2, 3, 4, 5) were synthesized. After that, the corresponding polymers (PnCOOCh, n = 1, 2, 3, 4, 5) were obtained by free radical polymerization. The molecular structure, composition and thermal behaviors of monomers and polymers were confirmed by 1H NMR, FTIR, single crystal diffractometer, GPC, DSC and TGA. The results indicate that although their molecular weights are not high, all the polymers have high glass transition (Tg) and degradation temperature. In addition, Tg gradually decreases with increasing of alkyl chain lengths, and the degradation temperature increases with the increase of carbon number.
- Yu, Yun-Long,Bai, Jun-Wei,Zhang, Jun-Hua
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experimental part
p. 1 - 6
(2012/08/08)
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- Synthesis and in vitro antibacterial activity of novel steroidal (6R)-spiro-1,3,4-thiadiazoline derivatives
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Novel steroidal (6R)-spiro-1,3,4-thiadiazoline derivatives were synthesized by the cyclization of steroidal thiosemicarbazones with acetic anhydride, screened in vitro against antibacterial activity using disc-diffusion method and the minimum inhibitory concentration. The results showed that steroidal thiadiazoline derivatives exhibited better antibacterial activity than the steroidal thiosemicarbazone derivatives. Chloro and acetoxy substituents on the 3β-position of the steroidal thiadiazoline ring increased the antibacterial activity. Among all the compounds, compound 7 and 8 were found better inhibitors of both types of bacteria (Gram-positive and Gram-negative) as compared to the respective drug amoxicillin. All the synthesized compounds were well characterized by spectroscopic methods such as IR, 1H-NMR, 13C-NMR mass, and elemental analysis and their stereochemistry was also discussed.
- Khan, Salman A.,Asiri, Abdullah M.
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p. 1452 - 1457
(2013/02/23)
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- Solvent free, highly chemoselective N and O-acylation on silica and silica magnesium oxide: A recyclable solid surface
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Silica or silica/magnesium oxide mixed surface mediates the N and O-acylation, benzoylation or sulfonylation of hosts of substrates under solvent free conditions at ambient temperature with high chemoselectivity.
- Ghosh, Pranab,Mandal, Amitava
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p. 261 - 268
(2012/10/29)
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- Synthesis, characterization and application of poly(4-vinylpyridine)- supported Bronsted acid as reusable catalyst for acetylation reaction
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Poly(4-vinylpyridine)-supported Bronsted acids (P4VP-HX) were prepared by wet impregnation technique. These supported acids were found as efficient heterogeneous green catalysts for acetylation of alcohol, amine and phenol with different catalytic activities. The wide application of P4VP-HX as reusable solid acid catalyst in organic reactions is possible because of its simple preparation and handling, stability, simple work up procedure.
- Borah, Kalyan Jyoti,Dutta, Papia,Borah, Ruli
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experimental part
p. 225 - 228
(2011/11/06)
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- DABCO: An efficient promoter for the acetylation of carbohydrates and other substances under solvent-free conditions
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A simple, mild and efficient solvent-free method for the acetylation of carbohydrates, and their partially protected derivatives, as well as non-carbohydrate substances in excellent yields in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is described with the advantage of tolerance to various functional groups, short reaction time and ease of product isolation.
- Ch, Ratnasekhar,Tyagi, Mohit,Patil, Premanand Ramrao,Kartha, K.P. Ravindranathan
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experimental part
p. 5841 - 5846
(2011/12/03)
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- Synthesis of 7-dehydrocholesterol through hexacarbonyl molybdenum catalyzed elimination reaction
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The efficiency of hexacarbonyl molybdenum catalyzed elimination reaction of the allylic acetates has been improved by the presence of O,N- bis(trimethylsilyl) acetamide in the reaction medium. The methodology is particularly well employed for the elimination of 7-acetoxycholesterol-3- acetate(cholestrol-3,7-diacetate) for which the resulting product obtained was exclusively 5,7-homoannular diene(7-dehydrocholesterol-3-acetate). Good yield is achieved (up to 70 %) while decreasing the side products formation and reducing the costs as compared to the previously used procedures. Hexacarbonyl molybdenum elimination reaction is greatly influenced by the reaction temperature, at low as well as at high temperature low yield of the homoannular diene product is separated while at moderate conditions of temperature high products formation is observed.
- Ur Rahman, Faiz,Tan, Tian Wei
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experimental part
p. 247 - 254
(2012/05/05)
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- Palladium-catalyzed oxidation of vinyl ether to acetate with hydrogen peroxide
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The selective hydrogen peroxide oxidation of vinyl ethers to give acetates was developed using triphenylphosphine palladium and triethyl amine catalysts under mild reaction conditions.
- Kon, Yoshihiro,Chishiro, Takefumi,Imao, Daisuke,Nakashima, Takuya,Nagamine, Takashi,Hachiya, Houjin,Sato, Kazuhiko
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supporting information; experimental part
p. 6739 - 6742
(2011/12/22)
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- A selective electrochemical method of glycosylation of 3β-hydroxy-Δ5-steroids
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A new electrochemical glycosylation method is presented. According to the method cholesterol and other 3β-hydroxy-Δ5-steroids can be selectively transformed to glycosides using non-activated sugars. The method is also useful for the synthesis of glycoconjugates with sugar linked to a steroid moiety by an ether bond.
- Morzycki, Jacek W.,?otowski, Zenon,Siergiejczyk, Leszek,Wa?ejko, Piotr,Witkowski, Stanis?aw,Kowalski, Jan,P?oszyn?ska, Jolanta,Sobkowiak, Andrzej
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experimental part
p. 1051 - 1055
(2010/08/20)
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- Synthesis and biological evaluation of some thiazolidinone derivatives of steroid as antibacterial agents
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Steroidal thiazolidinone derivatives were prepared by the multi-step reactions of steroid. It is prepared from steroidal thiosemicarbazones with ethyl bromoacetate in dioxane. Steroidal thiosemicarbazones were prepared by the reaction of thiosemicarbazide with steroidal ketones. The structures of these compounds were elucidated by IR, 1H NMR, Fab mass spectrometries and their purities were confirmed by elemental analyses. The antibacterial activity of these compounds was evaluated by the disk diffusion assay against two Gram-positive and two Gram-negative bacteria and then the minimum inhibitory concentration (MIC) of compounds was determined. The results showed that steroidal thiazolidinone derivatives are better in inhibiting the growth as compared to steroidal thiosemicarbazone derivatives of both types of the bacteria (Gram-positive and Gram-negative). Compounds 7 and 8 are better antibacterial agents as compared to standard drug Amoxicillin.
- Khan, Salman Ahmad,Yusuf, Mohammed
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scheme or table
p. 2597 - 2600
(2009/10/09)
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- Microwave-assisted cross-coupling and hydrogenation chemistry by using heterogeneous transition-metal catalysts: An evaluation of the role of selective catalyst heating
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The concept of specific microwave effects in solid/liquid catalytic processes resulting from the selective heating of a microwave-absorbing heterogeneous transition-metal catalyst by using 2.45 GHz microwave irradiation was evaluated. As model transformations Ni/C-, Cu/C-, Pd/C-, and Pd/ Al 2O3-catalyzed carbon-carbon/ carbon-heteroatom cross-couplings and hydrogenation reactions were investigated. To probe the existence of specific microwave effects by means of selective catalyst heating in these transformations, control experiments comparing microwave dielectric heating and conventional thermal heating at the same reaction temperature were performed. Although the supported metal catalysts were experimentally found to be strongly microwave absorbing, for all chemistry examples investigated herein no differences in reaction rate or selectivity between microwave and conventional heating experiments under carefully controlled conditions were observed. This was true also for reactions that use low-absorbing or microwave transparent solvents, and was independent of the microwave absorbtivity of the catalyst support material. In the case of hydrogenation reactions, the stirring speed was found to be a critical factor on the mass transfer between gas and liquid phase, influencing the rate of the hydrogenation in both microwave and conventionally heated experiments.
- Irfan, Muhammed,Fuchs, Michael,Glasnov, Toma N.,Kappe, C. Oliver
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experimental part
p. 11608 - 11618
(2010/05/17)
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- J-based analysis and DFT-NMR assignments of natural complex molecules: Application to 3β,7-dihydroxy-5,6-epoxycholestanes
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In order to reproduce the stereochemical dispositions of the epoxy and hydroxy functionalities, four 3β,7-hydroxy-5,6-epoxycholestanes were easily prepared from cholesterol, and their NMR spectroscopic data were experimentally obtained from 1D and 2D NMR experiments. An exhaustive QM-J-based analysis was then performed to replicate the experimental H-H and C-H coupling constants as well as the 13C NMR chemical shifts. The B3LYP GIAO methodology with the 6-311-G(d,p) basis set was chosen and showed that the data obtained from rings A and B were sufficient to calculate the correct stereochemistry of the 5,6-epoxy and 7-hydroxy groups. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
- Poza, Jesus Javier,Jimenez, Carlos,Rodriguez, Jaime
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experimental part
p. 3960 - 3969
(2009/04/08)
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